In U.S. Pat. No. 4,507,913, a desirable apparatus for vacuum spinning of yarn has been disclosed. The apparatus of that patent is very useful for the production of yarn in an efficient manner, however the yarn produced thereby does not have as much versatility--use in a large variety of different fabrics having different purposes--as desired.
According to the present invention, an apparatus is provided which is an improvement over the apparatus in said U.S. Pat. No. 4,507,913. The apparatus according to the present invention allows the production of yarn having a number of better properties than the yarn usually produced by the apparatus of said U.S. Pat. No. 4,507,913, including enhanced uniformity.
The apparatus according to the invention, like that in said co-pending application, includes an elongated hollow shaft having first and second ends, with a through-extending passageway, and at least a portion of the entire circumference of the shaft is perforated. Means are provided for mounting the shaft for rotation about an axis, and means are provided for rotating the shaft about its axis. Also means are provided for passing textile fibers through the through-extending passageway of the shaft linearly, generally along the axis of rotation, the fibers being fed into the first end of the shaft. Means are also provided for applying a vacuum to the exterior of the shaft so that at least some of the fibers or free ends of fibers passing through the shaft will draw toward the shaft perforations, and will be caused to rotate with the shaft as the fibers move linearly generally along the axis of rotation. Also means are provided for withdrawing formed yarn from the second end of the shaft, opposite the first end.
One of the major distinctions of the apparatus of the invention compared to that in said U.S. Pat. No. 4,507,913 is the construction and positioning of the perforations of the shaft. According to the invention, perforations are provided that slant in the direction of the second end from the through-extending passageway. The slanting perforations provide a more even flow of air from the exterior of the shaft to the vacuum source, with desirable results on the yarn production. It has also been found that only perforations adjacent the first end of the shaft are necessary, additional perforations further on down the shaft not performing any significant function, and that only four perforations--preferably equally spaced around the periphery of the shaft in a plane perpendicular to the axis of rotation of the shaft --are all that are necessary.
Another significant feature of the apparatus according to the present invention, vis-a-vis that of said U.S. Pat. No. 4,507,913, is the provision of a vacuum reservoir within the shaft itself in communication with the perforations. The vacuum reservoir preferably is a spherical opening within the shaft, with a common plane containing the four perforations generally at the center of the sphere. The vacuum reservoir provides for better wrapping action of fiber ends, resulting in the production of a stronger yarn.
Yet another significant distinction of the apparatus according to the invention, vis-a-vis that shown in said co-pending application, is the provision of a diffuser surrounding the shaft. The diffuser primarily assists in providing a more even wrap of the fibers, this again contributing to yarn strength. Also the diffuser assists in preventing the fibers from going out the perforations at start-up, or during other operating conditions, and it is desirable to have the diffuser mounted so that elongated slots therein can either be aligned with the perforations in the shaft (the normal desired configuration for optimum wrapping action), or the diffuser slots can be misaligned, which can result in "effects" in the yarn being produced.
The through-extending passageway in the shaft preferably has a larger diameter at the first end of the shaft than at the second end of the shaft. The diameter at the first end of the shaft, up to the vacuum reservoir, typically could be twice that in that portion of the shaft from the vacuum reservoir to the second end thereof. This distinction of the apparatus according to the invention compared to that in said U.S. Pat. No. 4,507,913 causes the air flow to concentrate adjacent the entry end of the shaft, and results in more desirable wrapping and therefore an improved yarn.
While the shaft of the apparatus according to the present invention may be rotated by action of the air flow upon vanes, as in said U.S. Pat. No. 4,507,913, it is more desirable to provide for the rotation to be effected by a conventional positive drive system utilizing pulleys and a belt. A motor rotates one pulley, which through the belt causes a pulley attached to the shaft to rotate. This results in a more controllable, much more uniform speed than can be achieved when most vacuum sources are utilized, since the average vacuum source tends to pulsate to a certain extent.
Utilizing the apparatus according to the present invention, it is possible to produce a yarn much faster than by ring spinning (for instance on the order of approximately 150 yards per minute), with a strength between that of ring spun yarn and yarn spun by air jets (such as Murata air jets). Yarn can be produced utilizing 100 percent wool, polyester/wool combinations, all cotton, and cotton/polyester combinations. Also, a number of different types and effects of yarn can readily be produced, as disclosed in co-pending application Ser. No. 680,510 filed Dec. 11, 1984, of Elbert F. Morrison for "Spinning With Vacuum". Further, according to the invention the yarn can be produced with selected properties, which properties need not be optimum properties, but can vary greatly.
It is the primary object of the present invention to provide an apparatus capable of producing good quality yarn at relatively high speed, and to produce such yarn. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.